怎么用java新建一个数据库表！用java语言

就是JPA是吧,你要在数据库里新建一个数据库,然后在属性文件里配置连接参数,前期工作做好了,这里我贴出我以前项目代码给你看,服务器一运行就会自动创建表的.
//////////////////////////////////////////////////////////////////////////
//
// Copyright 2010 Ningbo Safe Software Co.Ltd, All Right reserved.
//
//////////////////////////////////////////////////////////////////////////

package cn.credit.bean.information.cases;

import java.io.Serializable;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

//************************************************************************
/**
* 系统名 : 信用物流系统平台 模块名 : 资讯系统 功能名 : 成功案例
*
* @author meiwx
* @version 1.0 Aug 13, 2010 作成
*
*/
// ************************************************************************
@Entity
@Table(name = "TAB_CASES")
public class Cases implements Serializable {

private static final long serialVersionUID = 1L;
/* 审核员 */
private String assessor;
/* 状态 */
private String status;
/* 编码 */
private String id;
/* 标题 */
private String title;
/* 内容 */
private String content;
/* 分类 */
private String sort;
/* 作者 */
private String author;
/* 删除区分 */
private char del_flg;
/* 登录时间 */
private Date insert_time;
/* 更新时间 */
private Date update_time;
/* 录入员 */
private String update_user;
/* 发布时间 */
private Date issue_time;

/**
*
*
* @return
*/
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "ISSUE_TIME", length = 20)
public Date getIssue_time() {
return issue_time;
}

public void setIssue_time(Date issue_time) {
this.issue_time = issue_time;
}

/**
*
* @return String
*/
@Id
@Column(name = "ID", length = 10, nullable = false)
public String getId() {
return id;
}

/**
*
* @param id
*/
public void setId(String id) {
this.id = id;
}

/**
*
* @return
*/
@Column(name = "STATUS", length = 1, nullable = false)
public String getStatus() {
return status;
}

/**
*
* @return
*/
@Column(name = "TITLE", length = 20)
public String getTitle() {
return title;
}

/**
*
* @param title
*/
public void setTitle(String title) {
this.title = title;
}

/**
*
* @return
*/
@Column(name = "CONTENT", length = 21000)
public String getContent() {
return content;
}

/**
*
* @param content
*/
public void setContent(String content) {
this.content = content;
}

/**
*
* @return
*/
@Column(name = "SORT", nullable = false, length = 1)
public String getSort() {
return sort;
}

/**
*
* @param sort
*/
public void setSort(String sort) {
this.sort = sort;
}

/**
*
* @return String
*/
@Column(name = "AUTHOR", length = 10)
public String getAuthor() {
return author;
}

/**
*
*/
@Column(name = "ASSESSOR")
public String getAssessor() {
return assessor;
}

public void setAssessor(String assessor) {
this.assessor = assessor;
}

public void setStatus(String status) {
this.status = status;
}

/**
*
* @param author
*/
public void setAuthor(String author) {
this.author = author;
}

/**
*
* @return
*/
@Column(name = "DEL_FLG", length = 1)
public char getDel_flg() {
return del_flg;
}

public void setDel_flg(char del_flg) {
this.del_flg = del_flg;
}

/**
*
* @return
*/
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "INSERT_TIME", nullable = false)
public Date getInsert_time() {
return insert_time;
}

/**
*
* @param insert_time
*/
public void setInsert_time(Date insert_time) {
this.insert_time = insert_time;
}

/**
*
* @return
*/
@Temporal(TemporalType.TIMESTAMP)
@Column(name = "UPDATE_TIME", nullable = false)
public Date getUpdate_time() {
return update_time;
}

/**
*
* @param update_time
*/
public void setUpdate_time(Date update_time) {
this.update_time = update_time;
}

@Column(name = "UPDATE_USER", nullable = false)
public String getUpdate_user() {
return update_user;
}

public void setUpdate_user(String update_user) {
this.update_user = update_user;
}

}

java使用jdbc操作数据库。一般步骤：先获得数据库连接，再写建表SQL，并创建Statement，然后执行。